This invention relates to the denuding of a sodium-mercury amalgam to produce a sodium alcoholate. In particular, it relates to denuding the amalgam using a C.sub.1 to C.sub.4 alcohol in the presence of a catalyst of tungsten carbide, iron treated high density carbon, iridium, ruthenium, or mixtures thereof.
Sodium methylate, NaOCH.sub.3, is of commercial importance in making pharmaceuticals, perfumes, metallic soaps, dyes, and organic intermediates. Sodium methylate can be made as a by-product in the manufacture of chlorine using a mercury chlor-alkali cell. In a mercury chlor-alkali cell, brine is electrolyzed to produce chlorine and a sodium-mercury amalgam. To recover the mercury in the amalgam for reuse in the cell, the amalgam is sent to a denuder where the sodium in the amalgam is stripped from the mercury by either an aqueous process or a methanol process. In the aqueous process, the amalgam flows over a catalyst, such as carbon or carbon mixed with iron or molybdenum, and water reacts with the sodium in the amalgam to form sodium hydroxide according to the equation: EQU 2NaHg+2H.sub.2 O.fwdarw.2NaOH+H.sub.2 .uparw.+2Hg.
The aqueous process is illustrated in U.S. Pat. No. 4,161,433.
In the methanol process, methanol is used instead of water and sodium methylate is formed instead of caustic: EQU 2NaHg+CH.sub.3 OH.fwdarw.2NaOCH.sub.3 +H.sub.2 +2Hg.
The choice of whether to use the aqueous process or the methanol process depends on whether one wishes to produce caustic soda or sodium methylate, respectively. When the carbon or carbon-molybdenum or carbon-iron catalyst is used in the methanol process, the sodium methylate seems to poison the catalyst so that the efficiency of the denuding reaction falls significantly as sodium methylate is formed. A better catalyst would increase the production of sodium methylate and reduce the cost of making it.